Biogenic Silver Nanoparticles by Cacumen Platycladi Extract: Synthesis, Formation Mechanism, and Antibacterial Activity
Biogenic Silver Nanoparticles by Cacumen Platycladi Extract: Synthesis, Formation Mechanism, and Antibacterial Activity
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侧柏提取物生物银纳米粒子：合成、形成机制和抗菌活性
DOI：
10.1021/ie200858y
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发表时间：
2011-08-03
影响因子：
4.2
通讯作者：
Li, Qingbiao
中科院分区：
文献类型：
--
作者：
Huang, Jiale;Zhan, Guowu;Li, Qingbiao
研究了侧柏提取液生物合成银纳米颗粒的方法。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)、选区电子衍射(SAED)和X射线衍射仪(XRD)对AgNPs进行了表征。结果表明，在30℃和60℃下，随着AgNO3初始浓度的增加，AgNPs的平均尺寸增大，尺寸分布变宽，导致表面等离子体共振吸收红移和展宽。采用原子吸收光谱法(AAS)测定银离子转化率，并用3，5-二硝基水杨酸比色法、考马斯亮蓝比色法、苯酚-硫酸比色法、芦丁分光光度法、2，2-二苯基-1-苦基肼(DPPH)自由基清除法测定提取物中还原糖、黄酮类、糖类、蛋白质含量及抗氧化活性。结果表明，还原糖和类黄酮是银离子生物还原的主要原因，在90℃时，银离子的还原能力增强，形成了粒径分布较窄的AgNPs(18.4+/-4.6 nm)。最后，对所合成的AgNPs对大肠杆菌和金黄色葡萄球菌的抗菌活性进行了评价，以确定其在载银抗菌材料中的潜在应用。这项工作为生物合成技术的产业化和AgNPs的进一步抗菌应用提供了有用的技术参数。此外，通过测量植物提取物中生物分子浓度的变化来阐明银离子的生物还原机理，为理解此类生物成因银纳米粒子的形成机制提供了例证。
Biosynthesis of Ag nanoparticles (AgNPs) by Cacumen Platycladi extract was investigated. The AgNPs were characterized by ultraviolet visible absorption spectroscopy (UV-vis), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). The results showed that increasing the initial AgNO3 concentration at 30 or 60 degrees C increased the mean size and widened the size distribution of the AgNPs leading to red shift and broadening of the Surface Plasmon Resonance absorption. The conversion of silver ions was determined by atomic absorption spectroscopy (AAS) and to discuss the bioreductive mechanism, the reducing sugar, flavonoid, saccharide, protein contents in the extract, and the antioxidant activity were measured using 3,5-dinitrosalicylic acid colorimetric; Coomassie brilliant blue; phenol-sulfuric acid; rutin-based spectrophotometry method; and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay methods. The results showed that the reducing sugars and flavonoids were mainly responsible for the bioreduction of the silver ions and their reductive capability promoted at 90 degrees C, leading to the formation of AgNPs (18.4 +/- 4.6 nm) with narrow size distribution. Finally, the antibacterial activity of the AgNPs against E. coli and S. aureus was assessed to determine their potential applications in silver-loaded antibacterial materials. This work provides useful technical parameters for industrialization of the biosynthetic technique and further antibacterial application of the AgNPs. Furthermore, the elucidation of bioreductive mechanism of silver ions by measuring the change of the biomolecular concentrations in plant extract exemplifies understanding the formation mechanism of such biogenic AgNPs.